In a set of two simultaneous stealth raids in Libya and Somalia, the United States military Saturday delivered a double blow against al Qaeda terror leaders.

By far the most significant action, according to U.S. officials, was the reported capture outside Tripoli, Libya, of Anas al Libi, wanted for his role in the deadly bombings of two U.S. embassies in Africa in 1998.

"As the result of a U.S. counterterrorism operation, Abu Anas al Libi is currently lawfully detained by the U.S. military in a secure location outside of Libya," Pentagon Press Secretary George Little said.

Al Libi is now in custody on a U.S. Navy ship, according to U.S. military sources. Officials told ABC News he is expected to be handed over to the FBI for a flight to New York where he will stand trial on the terror charges.

The U.S. had posted a $5 million reward for the capture of al Libi, whose presence in Libya was known for several months to officials.

A military source said the capture of al Libi was carried out by 1st Special Forces Group Operational Detachment-Delta, aka "Delta Force," headquartered at Fort Bragg, North Carolina.

The second pre-dawn raid in another part of the African continent targeted leaders of the al Shabab terror group in Somalia, an affiliate of al Qaeda and the organization believed responsible for the attack on the Westgate Mall in Nairobi, Kenya.

"I can confirm that yesterday, October 4, U.S. military personnel were involved in a counter terrorism operation against a known al-Shabaab terrorist," Little said. "We are not prepared to provide additional detail at this time."

U.S. officials told ABC News that they have received conflicting accounts from "on the ground" about whether the unidentified principal target was killed or captured during the military raid.

A U.S. official told ABC News they can't identify who was killed.

A military officer familiar with the raid said that when the SEALs arrived at the target's location, there were a lot more people there than they expected and they started firing at the SEALs. They didn't know who they were "so they retreated," the officer said.

When asked how important the target was, the officer said: "When we put boots on the ground it is only for an important target."

The Somalia raid was a unilateral mission, involving only the U.S., the officer said.

The al Shabab raid was planned even before the mall attack, according to U.S. officials, but took on added urgency afterwards.

The raids were synchronized to make sure the U.S. teams had the element of surprise in both cases.

Historically, raids of this sort are run by the Joint Special Operations Command, headquartered at Fort Bragg, N.C. Navy SEAL Team Six is the group responsible for the Somalia raid, according to our military source.

This is the same "Tier One special mission unit" that carried out the Capt. Phillips rescue, operating out of Manda Bay in Kenya, and the raid in which al Qaeda leader Osama bin Laden was killed.